When installing underground cables, wire and pipe, it is often uneconomical or even impossible to employ traditional excavation methods in order to bury the cable, wire or pipe. For example, when cable, wire or pipe is to be installed beneath existing roads, sidewalks or railroad tracks, the cost and expense of excavation and rebuilding is such that a construction project may be rendered impossible. Even when there are no such obstacles, it may be desirable for aesthetic, time, monetary and other reasons to install underground cable, wire, pipe or other device underground without disturbing the ground surface.
In order to address this need, the field of horizontal subterranean drilling has arisen. In order to install devices underground, first a generally horizontal underground bore hole is drilled beneath the ground at a desired depth (such as 2-15 feet). The bore hole may then be reamed out to any desired diameter. Next, the desired device is installed. Surface reclamation work is necessary only at the entry and the terminus of the bore hole.
Several embodiments and several features of drill bit structures are depicted herein. Those features may be utilized singly or in combination to arrive at a steerable horizontal subterranean drilling device which offers one or more advantages over existing steerable horizontal subterranean drilling devices. Objects, features and advantages of the devices and structures depicted herein will become apparent to persons of ordinary skill in the art upon reading this document in conjunction with the appended drawings, and upon utilizing and testing steerable horizontal subterranean drilling devices which incorporate one or more of the features described below.